Line Pipe Thickness

It's a conspiracy (or just a piracy) on the part of safety fanatics to get folks to buy heavier-walled pipe.

Or maybe an urban legend? (I'm not sure this is true to start with.)

Or just a wrong formula, such as $ = kdl/t?

maybe supply and demand and economies of scale

Because having thinner thickness needs more force for forming or extrusion

and also sometimes extra processing is required

also the percentage of scrap is higher

I would be curious to know your exact circumstances. Be it ferrous, non-ferrous, fiberglass, poly, etc I have never run into this situation. Thicker pipe always costs more in my neck of the woods.

I think is is simple logic:

The total cost of the pipe comprises of many factors like: (Here we are comparing the pipes with same OD or ID but varying thickness)

1. Material Cost: This reduces with reduced thickness. Probably, you are considering this factor only, while raising your thread. This factor is less dominant in total cost of the pipe.

2. Process Cost: The process cost per length remains same. Thus, process cost per Kg increases as the weight (means thickness) reduces.

3. Transport cost: This is complex calculation. Weight reduces with reduced thickness, but the volume for all pipes remain same. The transport cost is calculated by some complex formula, where both weight and volume is considered. Then volume consideration is predominant, the cost per weight increases.

Thus, effectively. the cost increases with reduced thickness.

I beleive in opposite for same length of pipes. More of material will cost more, if other things are similar. You should not generalise your experience. It may be a specific and stray case for a perticular type of pipe(for ex- seamless etc.) or of specific material(for ex- SS, non-ferrous, plastic etc.).

If you are comparing the price per unit weight basis, then definetly thicker the pipe lower the cost. Please check.